US2218125A - Railway track circuit apparatus - Google Patents

Description

Oct. 1940. P,`P. soslNsKl 2,218,125 I RAILWAY TRACK CIRCUITAPPARATUS Filed Aug. l5, 1934 INvgNToR Paul P. Sosmslfz H I S ATTORNEY Patented Get. 15, 194i@ gPA'iil-I.NLT OFFICEQ RAILWAY TRACK CIRCUIT AIPARATU Paul P. Sosinski, Edgewood, Pa.,. assignor to The Union Switch & Signal Company,

Swissvale,

Paga corporation of Pennsylvania I Application August 15, wetsuit! Np. 739,946

21 Claims.

My invention relates to railway signaling apparatus of the type involving track circuits, and has for anobject theprovisio-n, in apparatus of this type, of a novel and improved track circuit including'a relay which will-respond to the decrease in current supplied to it when the train yenters the associated section, but which will not respond to' track circuitcurrent of steady value or to gradual changes in the current supplied to the relay due for example to changes in ballast conditions.

I Willv describe two `forms of apparatus embodying my invention, and will then point outl the novel features thereof in claims. l5 In the accompanying drawing, Fig. 1 is a diagrammatic View showing one form of 'apparatus embodying my invention. Fig. 2 is a View showing a modification of al portion of the apparatus shown in Fig; 1, and also embodying my invention.

Similar reference characters refer to similar parts in each of the views.

Referring first to Fig, 1, the reference characters I and ia designate' the track rails of a stretch of railway track along which traic normally moves in the direction indicated by the arrow. These 'rails are divided by insulated joints 2 to form a plurality of tracksections, of which only one complete section, D-E, is shown in the drawing. Traflcmo-ving through section D-E from left toi right is governed by a signal K, which, as here shown, is a light signal comprising a proceed lamp G, a .caution lamp Y, and a stop lamp R.

Section D-E is provided with a track circuit comprising a battery H connected across the rails at the exit end of the section and a neutral relay P, a transformer T and a neutral relay A, all receiving'energy from the lrails at the entering end of thev section.` vRelay P has a holding 40 circuit which passes from rail I, through the primary 3 of the transformer T, a portion 6 of the operating winding of the relay P, a resistance?, a front Contact 8 of the relay'P, and a back contact 5 of the relay A to rail Ia. Relay P also has a pickup circuit which passes from rail I through the primary 3 of the transformer T, the entire operating winding of the relay P, and a back contact I I of `a relay S to rail Ia. The secondary 4 of the transformer T is connected, in series with a rectiiier Q, to the operating Winding of the relay A.

Relay S is a neutral relay controlled by a front contact 9 of the relay P and `energized by a battery I0. I y j 1 Associated-withrelays A, vPy and S. isa fourth relay F, which visa distant relay controlled by the following cir'cuitzlirom terminal B ora suite able source of current at location E, throughfront contact I3 of relay S1 at location E, and Winding of relay F, 'to terminal Cl cf the same 'source of 5 current. j v f The proceed lamp G is provided with a circuit which passes lfrom terminal B, through front Contact I2 of relayv S, front contact Il l of relay n F, and lamp Gto terminal C of the same source 10 of fcurrent. The caution lampY Y is provided fwith `a circuit which passes from terminaljB, through front point of contact I2 of relay S,fback point of Contact I4 of relay F, and lamp Y to ter'- l' minal C. `The stop lamp R- is provided with a 15 circuit which'passesfrom terminal B, 'through back point of .contact I2 of relay S,kand lamp R toterminalC. y

The operation of the system is as follows: When section D-E unoccupied, relay A is de energized, relay P'is energized by currentvfro-m battery H," and relay S is energized bycurrent from battery I0. If the section nextin advance isfalso unoccupied, relay F is energized. Lamp G will then be lightedso that the signa-lwill in'- dicate proceed.' If, however; the sectionin advanl'oe'of'point'fE isoccupied-by a. train, relay F will be deenergized, so that'larnp Y will' be lighted and signal K will indilfate caution. e I will" now assume that a train entersA section 30 D-E. l When this`occurs, the shunt aiforded by the wheels and axles Yof suchv train will'suddenly reduce the "amount of current flowing in primary 3 of transformer T, and this sudden change in the primary current will induce an impulse of current in secondary 4' of such polarity as to momentarily'energize relay A, opening back contact 5. The momentaryopening of back contact 5 `will open the'holding circuit for relay P which: Y in turn will'release relay S. The deenergization 40 of relay S Ywilll open 4the -circuit for the proceed lamp G or the caution lamp Y at front 'point of contact I2 of relay S and'will'close the circuit for stop lamp'Rfat backpoint of contact'LI2. Signal K willthenndicate stop.A Relay P will re- 45 main downdue tothe train shunt so long'assection D'-E is'occupied by a train. When the traint leaves section D-E, there will be a suddenfincre'asey in the amount ofcurre'nt supplied to primary 3 of transformer T and this sudden change -in the primary current will'cause an impulse tobe induced in secondary vI of a polarity opposite' to .that Igenerated whenr the train entered the section.A Rectier Q willprevent they ilow'of lthis vcurrent of opposite polarity through the winding of relay A and relay A will not be energized. Relay P will be energized by the pickup circuit which includes the full winding S and back contact Il of relay S. The energization of relay P will energize relay S through front contact 9 of relay P. The energization of relay S will open the pickup circuit and restore the holding circuit for relay P. Relay F will have become deenergized due to thetrain entering the section in advance of section D-E, and so signal K will indicate caution until the train passes out of such section in advance, when it will again indicate proceed.

Rectifier Q is not essential, however, because a momentary pickup of relay A, when the train leaves the section D-E, is of no consequence, since back contact 5 of relay A has ample time to reclose and thus establish theholding circuit for relay P through iront contact 8 of relay P, before the pickup circuit for relay P is opened by back contact ll of relay S. i

The operation of relay A is independent of the track energy level at the left-hand end of section,D-E, and is `dependent only on the change inthe amount of current supplied to transformer T when a train enters the section. It follows that changes in the characteristics of the track circuit due to variations in weather or other conditions will not affect `the operation of this relay. Relay A is sufficiently sensitive to respond to a small change in the track circuit current such as would occur when the track is shunted during wet ballast conditions, therefore, a relatively poor shunt would actuate relay A during dry ballast conditions because of the relatively large change in the track circuit current. f Relay P, however, if relay A were not used, would require a relatively good shunt for releasing under dry ballast conditions. The combination of the two relays A `and P provides, therefore, for reliable shunting under all possible conditions oi the track.

`Referring now-to Fig. 2, the apparatus shown in this view is the same as that shown in Fig. 1, except that relay A receives energy from a secondary winding 4fab of relay P wound in inductive relation to the operating winding of relay P.

With this arrangement, the maximum energization'of relay P, which would ordinarily obtain under dry ballast'conditions, must not begreat enough to saturate the relay core as, otherwise, the train shunt may not produce a Suflcient change in the ux to operate relay A. The apparatus shown in Fig. 2 is otherwise the same as that shown in Fig. 1'. l v

, Although I have herein shown and described only two'forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a sectionof railway track, a source of current connected across the rails of said section, a relay receivingenergy from the rails of said section and responsive to the steady value of current with which it isl supplied, and mearis also receiving energy from the rails of said section and responsive to the change in value of `the current received thereby due to the entrance'of a train into said section but not responsive to the steady value of such current for momentarily disconnecting said relay from at least one rail of said section. Y

.l 2. In combination,` a section of railway track,

a source of current connected across the rails of said section, a relay receiving energy from the rails of said section and responsive to the steady value of the current with which it is supplied, and a second relay also receiving energy from' the rails of said section and responsive to the change in the value of the current received thereby due to the entrance of atrain into said section but not responsive to the steady value of such current, said second relay having an arma- 4ture actuating a contact for momentarily disconnecting said rst relay from one rail of said section.

3. In combination, a section of railway track, a source of current connected across the rails at one end of said section, a first relay receiving energy from the rails at the other end of said section and responsive to the steady value of current with which it is supplied, a second relay, means also receiving energy from the rails at said other end of the section for energizing said second relay when the value of the current received by said means is changed due to the entrance of a train into said section, said means being incapable of responding to the steady value of such current, and means controlled by said second relay for decreasing the energization of said rst relay below the release point thereof.

4. In combination, a section of railway track, a source of current connected across the rails of said section, a primary relay, a secondary relay, a holding circuit for said primary relay connected across the rails of said section and including only a portion of the operating winding of the primary relay and a resistance, a pickup circuit for said primary relay also connected across the rails of said section and including the entire operating winding of said primary relay and a back contact of said secondary relay, a circuit for said secondary relay including a front contact of said primary relay and a source of current, and means also receiving energy from the rails of said section and responsive to the change in the value of the current received thereby due to the entrance 'of a train into said section for momentarily opening said holding circuit for said primary relay.

5. In combination, a section of railway track, a source of current connected across the rails of said section, a primary relay, a secondary relay, a holding circuit for said primary relay connected across the rails of said section and including only a portion of the Aoperating winding of the primary relay and a resistance, a pickup circuit for said primary relay also connected across the rails of said section and including the entire operating winding of said primary relay and a back contact of said secondary relay, a circuit for said secondary relay including a front contact of said primary relay and a source of current, and a third relay also receiving energy from the rails of said sectionand responsive to the change in the value of the current received thereby due to the entrance of a train into said section and having an armature actuating a contact for momentarily disconnecting said primary relay from one rail of said section.

6. In combination, a section of railway track, a source of current connected across the rails of said section, a primary relay, a secondary relay, a holding circuit for said primary relay connected across the rails of said section and including only a portion of the operating Winding of the primary relay and a resistance, a pickup circuit for said primary relay also connected elfi fir!

across the rails of,y said section andincluding the entire operating winding of saidprimary relay and a back contact of said secondary relay, a circuit for said secondary relay including a front contact of said primary relay and a source of current, a third relay,'means also receiving energy from the rails of said section for energizing said third relay when the value of the current received by said means is changed due to the entrance of a train into said section, and means controlled by said third relay for decreasing the energization of `said primary relay below the release point thereof.

7. In combination; a section of railway track,

a source of current connected across the rails of said section, a primary relay having a holding circuit receiving energy from `the railsrof ,said section and including a front contact of the lprimary relay, a secondary relay controlled by a front contact of said primary relay, a pickup circuit for said primary relay receiving energy from the rails of said section andincluding a back contact of said secondary relay, and means also receiving energy from th'evrails of said section and responsive to the change inthe value of the current received thereby due to the entrance of a train into said section for momentarily opening said holding circuit for said primary relay.

, 8. In combination, asection of railway track, a source of current connected across the rails of said section, a primary relay having a holding `circuit receiving energy from the rails of said section and including a front contact of the primary relay, asecondary relay controlled by a iront con- -tact of said primary relay, a pickup circuit for said primary relay receiving energy from the rails of said section and including a back Ycontact of said' secondary relay, and atthird-relay also receiving energy fromV the rails of said section through a secondary Winding of said primary relay .and responsive to the change in the value of the current received thereby due to the entrance of a train in said section, said third relay having an armature actuating a contact for momentarily disconnecting said primary relay from one rail of said section.

9. In combination, a section of railway track, a source of current connected across the rails of said section, a primary relay having a holding circuit receiving energy from the rails of said section and including a front contact of the primary relay, a secondary relay controlled by a front contact of said primary relay, a pickup circuit for said primary relay receiving energy from the rails of said section and including a back contact of said secondary relay, said primary relay having fa secondary winding in inductive relationV to the operating winding, a third relay connected to said secondary winding and responsive to the change in the value of the current received thereby due to the entrance of a train in said section, said third relay having an armature actuating a contact for momentarily disconnecting said primary relay from one rail of said section.

10. In combination, a section of railway track, a source of current connected across the rails of said section, a track relay receiving energy from the rails of said section and responsive to the steady value of current with which it is supplied, a transformer also receiving energy from the rails of said section, and means including a'normally deenergized auxiliary relay which becomes momentarily energized from said transformer in response to a change in the energization of the transformer occurring upon the' entrance of a traininto said section for decreasing the energizationofisaid track relay' below the release point thereof. V- n 11. In combination, a section of railway track, a source of current connected across the rails of said section, ajmain relay receiving energy from the rails or said section and responsive to the steady value of current with which it is supplied, a transformer having a primary which receives energy from the rails of said section, a normally deenergized auxiliary relay receiving energy momentarilyV from the secondary of said transformer in response to a change in the energy received by said primary occurring upon the entrance of a train into said section, and means controlled by said auxiliary relay for decreasing the energization of said main relay below the release point thereof.

12. In combination, a section of railway track, a source of current connected across the rails of said section, a first relay receiving energy from the rails of said section .and responsive to the lsteady value of current with which it is supplied, a rectifier, a second relay having an operating circuit which includes said rectier, means ,also -receiving energy from the rails of said section for energizing said operating circuit when the value of the current received by said means is changed due to the entrance of a train into said section, said means being incapable ofenergizing said operating circuit in response to a steady value ofsuch current, and means controlled by said second relay for decreasing( the energization of said first relay below the release point thereof.

13. In combination with a section of railway track and a source of current connected across the rails of saidsection, a rrelayhaving an'op'erating winding receiving current from the rails of said section and having a second winding in in'- ductive relation with said operating winding, an auxiliary relay controlled by the current induced in said second winding when said section becomes occupied by a train, `,and means governed by said auxiliary relay for controlling the supply of current to said operating winding.

14. A track circuit for railroads comprising, in combination, a section of railway track, a source of unidirectional current connected across the track rails iat one end of said section, a track relay receiving energy from the track rails at the other end of said section, a transformer having its primary winding included in said track circuit at said otherV end of the section, and an auxiliary relay :also at said other end of the section energized only by current induced in the secondary winding of said transformer, and operated in response to the relatively quick change of current in the track circuit caused by the entrance of a train into said section for decreasing the current through said track relayto release its armature.

15. A track circuit for railroads comprising, in

combination, a unidirectional source of current direction is induced in said secondary winding Y by the relatively quick change in the current in `release its armature.

said track circuit caused bythe entranceof a train upon said track circuit, said contact when operated to said particular position4 acting to decrease the current through' said track relay to 16. In combination, a section of railway track, a source of current connected across the rails of said section, a first relay receiving energy from the rails of said section and responsive to the steady value of current with which it is supplied, a normally deenergized second relay, means for momentarily energizing said second relay due to the relatively high'rate of change of current ow in said rst relay when the current through said rst relay is quickly decreased upon the entrance of a train into said section, and means controlled by said second relay when energized for decreasing the energization of said first relay below the release point thereof.

17. In combination, a sectionof railway track, a source of energy supplying current to the rails of said section, a relay receiving current from the rails of said section, and means responsive to the rate of change ofcurrent oW in said relay for completely disconnecting current from said relay when the current through the relay is rapidly decreased due to the entrance of a train into said section.

18. In combination, a section of railway track, a source of energy supplying current to the rails of said section, a relay receiving current from the rails of said section, a transformer having its primary also receiving current from the rails of said section, and means governed by the secondary of said transformer for completely disconnecting current frorn said relay upon a. decrease in the current owing in said primary due to the entrance of a train into said section.

19. In `a track circuit for railroads, the combination with a section of `railway track having a track relay connected thereto at one end of the section and a source of unidirectional current connected thereto at the other end of the section, a normally' deenergized auxiliary relay separate from said track relay and located at said one end of the section, said auxiliary relay being eiective when operated to decrease the current through'said track relay and thereby cause a release of its armature,r and means including a transformer also at'said one end of the section for causing a momentary operation of said auxiliary relay in response to the relatively quick change in the current in said track circuit caused bythe entrance of a train into said section. j

20. A track circuit for railroads comprising in combination, a track relay at one `encl of the track circuit, a source of unidirectional current at the other end of the track circuit for energizing said track relay, an inductive device at said one end of the track circuit, and a normally deenergized auxiliary relay also at said one end of the track circuit receiving operating energy from the track circuit through said inductive device in response to the relatively high rate of change in the current in said track circuit produced by the entrance of a train upon said track circuit for decreasing the current through said track relay and thereby causing a release of its armature.

21. In combination, a section of railroad track, a signal governing trafc over said section, a source of energy connected across the rails at one end of said section, a track relay connected across the rails at the other end of said section and responsive to the current 110W therein, electro-magnetic means responsive only to variations in current flow in said track circuit to assume a particular magnetized condition of only one polarity during such variations, and means jointly controlled by said track relay and said electromagnetic means for governing said signal.

PAUL P. SOSINSKI.

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